// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/command_line.h"

#include <algorithm>
#include <ostream>

#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"

#if defined(OS_WIN)
#include <windows.h>
#include <shellapi.h>
#endif

namespace base {

CommandLine* CommandLine::current_process_commandline_ = NULL;

namespace {

    const CommandLine::CharType kSwitchTerminator[] = FILE_PATH_LITERAL("--");
    const CommandLine::CharType kSwitchValueSeparator[] = FILE_PATH_LITERAL("=");

// Since we use a lazy match, make sure that longer versions (like "--") are
// listed before shorter versions (like "-") of similar prefixes.
#if defined(OS_WIN)
    // By putting slash last, we can control whether it is treaded as a switch
    // value by changing the value of switch_prefix_count to be one less than
    // the array size.
    const CommandLine::CharType* const kSwitchPrefixes[] = { L"--", L"-", L"/" };
#elif defined(OS_POSIX)
    // Unixes don't use slash as a switch.
    const CommandLine::CharType* const kSwitchPrefixes[] = { "--", "-" };
#endif
    size_t switch_prefix_count = arraysize(kSwitchPrefixes);

    size_t GetSwitchPrefixLength(const CommandLine::StringType& string)
    {
        for (size_t i = 0; i < switch_prefix_count; ++i) {
            CommandLine::StringType prefix(kSwitchPrefixes[i]);
            if (string.compare(0, prefix.length(), prefix) == 0)
                return prefix.length();
        }
        return 0;
    }

    // Fills in |switch_string| and |switch_value| if |string| is a switch.
    // This will preserve the input switch prefix in the output |switch_string|.
    bool IsSwitch(const CommandLine::StringType& string,
        CommandLine::StringType* switch_string,
        CommandLine::StringType* switch_value)
    {
        switch_string->clear();
        switch_value->clear();
        size_t prefix_length = GetSwitchPrefixLength(string);
        if (prefix_length == 0 || prefix_length == string.length())
            return false;

        const size_t equals_position = string.find(kSwitchValueSeparator);
        *switch_string = string.substr(0, equals_position);
        if (equals_position != CommandLine::StringType::npos)
            *switch_value = string.substr(equals_position + 1);
        return true;
    }

    // Append switches and arguments, keeping switches before arguments.
    void AppendSwitchesAndArguments(CommandLine* command_line,
        const CommandLine::StringVector& argv)
    {
        bool parse_switches = true;
        for (size_t i = 1; i < argv.size(); ++i) {
            CommandLine::StringType arg = argv[i];
#if defined(OS_WIN)
            TrimWhitespace(arg, TRIM_ALL, &arg);
#else
            TrimWhitespaceASCII(arg, TRIM_ALL, &arg);
#endif

            CommandLine::StringType switch_string;
            CommandLine::StringType switch_value;
            parse_switches &= (arg != kSwitchTerminator);
            if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
#if defined(OS_WIN)
                command_line->AppendSwitchNative(UTF16ToASCII(switch_string),
                    switch_value);
#elif defined(OS_POSIX)
                command_line->AppendSwitchNative(switch_string, switch_value);
#endif
            } else {
                command_line->AppendArgNative(arg);
            }
        }
    }

#if defined(OS_WIN)
    // Quote a string as necessary for CommandLineToArgvW compatiblity *on Windows*.
    string16 QuoteForCommandLineToArgvW(const string16& arg,
        bool quote_placeholders)
    {
        // We follow the quoting rules of CommandLineToArgvW.
        // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
        string16 quotable_chars(L" \\\"");
        // We may also be required to quote '%', which is commonly used in a command
        // line as a placeholder. (It may be substituted for a string with spaces.)
        if (quote_placeholders)
            quotable_chars.push_back(L'%');
        if (arg.find_first_of(quotable_chars) == string16::npos) {
            // No quoting necessary.
            return arg;
        }

        string16 out;
        out.push_back(L'"');
        for (size_t i = 0; i < arg.size(); ++i) {
            if (arg[i] == '\\') {
                // Find the extent of this run of backslashes.
                size_t start = i, end = start + 1;
                for (; end < arg.size() && arg[end] == '\\'; ++end) { }
                size_t backslash_count = end - start;

                // Backslashes are escapes only if the run is followed by a double quote.
                // Since we also will end the string with a double quote, we escape for
                // either a double quote or the end of the string.
                if (end == arg.size() || arg[end] == '"') {
                    // To quote, we need to output 2x as many backslashes.
                    backslash_count *= 2;
                }
                for (size_t j = 0; j < backslash_count; ++j)
                    out.push_back('\\');

                // Advance i to one before the end to balance i++ in loop.
                i = end - 1;
            } else if (arg[i] == '"') {
                out.push_back('\\');
                out.push_back('"');
            } else {
                out.push_back(arg[i]);
            }
        }
        out.push_back('"');

        return out;
    }
#endif

} // namespace

CommandLine::CommandLine(NoProgram no_program)
    : argv_(1)
    , begin_args_(1)
{
}

CommandLine::CommandLine(const FilePath& program)
    : argv_(1)
    , begin_args_(1)
{
    SetProgram(program);
}

CommandLine::CommandLine(int argc, const CommandLine::CharType* const* argv)
    : argv_(1)
    , begin_args_(1)
{
    InitFromArgv(argc, argv);
}

CommandLine::CommandLine(const StringVector& argv)
    : argv_(1)
    , begin_args_(1)
{
    InitFromArgv(argv);
}

CommandLine::CommandLine(const CommandLine& other)
    : argv_(other.argv_)
    , switches_(other.switches_)
    , begin_args_(other.begin_args_)
{
    ResetStringPieces();
}

CommandLine& CommandLine::operator=(const CommandLine& other)
{
    argv_ = other.argv_;
    switches_ = other.switches_;
    begin_args_ = other.begin_args_;
    ResetStringPieces();
    return *this;
}

CommandLine::~CommandLine()
{
}

#if defined(OS_WIN)
// static
void CommandLine::set_slash_is_not_a_switch()
{
    // The last switch prefix should be slash, so adjust the size to skip it.
    DCHECK_EQ(wcscmp(kSwitchPrefixes[arraysize(kSwitchPrefixes) - 1], L"/"), 0);
    switch_prefix_count = arraysize(kSwitchPrefixes) - 1;
}

// static
void CommandLine::InitUsingArgvForTesting(int argc, const char* const* argv)
{
    DCHECK(!current_process_commandline_);
    current_process_commandline_ = new CommandLine(NO_PROGRAM);
    // On Windows we need to convert the command line arguments to string16.
    base::CommandLine::StringVector argv_vector;
    for (int i = 0; i < argc; ++i)
        argv_vector.push_back(UTF8ToUTF16(argv[i]));
    current_process_commandline_->InitFromArgv(argv_vector);
}
#endif

// static
bool CommandLine::Init(int argc, const char* const* argv)
{
    if (current_process_commandline_) {
        // If this is intentional, Reset() must be called first. If we are using
        // the shared build mode, we have to share a single object across multiple
        // shared libraries.
        return false;
    }

    current_process_commandline_ = new CommandLine(NO_PROGRAM);
#if defined(OS_WIN)
    current_process_commandline_->ParseFromString(::GetCommandLineW());
#elif defined(OS_POSIX)
    current_process_commandline_->InitFromArgv(argc, argv);
#endif

    return true;
}

// static
void CommandLine::Reset()
{
    DCHECK(current_process_commandline_);
    delete current_process_commandline_;
    current_process_commandline_ = NULL;
}

// static
CommandLine* CommandLine::ForCurrentProcess()
{
    DCHECK(current_process_commandline_);
    return current_process_commandline_;
}

// static
bool CommandLine::InitializedForCurrentProcess()
{
    return !!current_process_commandline_;
}

#if defined(OS_WIN)
// static
CommandLine CommandLine::FromString(const string16& command_line)
{
    CommandLine cmd(NO_PROGRAM);
    cmd.ParseFromString(command_line);
    return cmd;
}
#endif

void CommandLine::InitFromArgv(int argc,
    const CommandLine::CharType* const* argv)
{
    StringVector new_argv;
    for (int i = 0; i < argc; ++i)
        new_argv.push_back(argv[i]);
    InitFromArgv(new_argv);
}

void CommandLine::InitFromArgv(const StringVector& argv)
{
    argv_ = StringVector(1);
    switches_.clear();
    switches_by_stringpiece_.clear();
    begin_args_ = 1;
    SetProgram(argv.empty() ? FilePath() : FilePath(argv[0]));
    AppendSwitchesAndArguments(this, argv);
}

FilePath CommandLine::GetProgram() const
{
    return FilePath(argv_[0]);
}

void CommandLine::SetProgram(const FilePath& program)
{
#if defined(OS_WIN)
    TrimWhitespace(program.value(), TRIM_ALL, &argv_[0]);
#else
    TrimWhitespaceASCII(program.value(), TRIM_ALL, &argv_[0]);
#endif
}

bool CommandLine::HasSwitch(const base::StringPiece& switch_string) const
{
    DCHECK_EQ(ToLowerASCII(switch_string), switch_string);
    return switches_by_stringpiece_.find(switch_string) != switches_by_stringpiece_.end();
}

bool CommandLine::HasSwitch(const char switch_constant[]) const
{
    return HasSwitch(base::StringPiece(switch_constant));
}

std::string CommandLine::GetSwitchValueASCII(
    const base::StringPiece& switch_string) const
{
    StringType value = GetSwitchValueNative(switch_string);
    if (!IsStringASCII(value)) {
        DLOG(WARNING) << "Value of switch (" << switch_string << ") must be ASCII.";
        return std::string();
    }
#if defined(OS_WIN)
    return UTF16ToASCII(value);
#else
    return value;
#endif
}

FilePath CommandLine::GetSwitchValuePath(
    const base::StringPiece& switch_string) const
{
    return FilePath(GetSwitchValueNative(switch_string));
}

CommandLine::StringType CommandLine::GetSwitchValueNative(
    const base::StringPiece& switch_string) const
{
    DCHECK_EQ(ToLowerASCII(switch_string), switch_string);
    auto result = switches_by_stringpiece_.find(switch_string);
    return result == switches_by_stringpiece_.end() ? StringType()
                                                    : *(result->second);
}

void CommandLine::AppendSwitch(const std::string& switch_string)
{
    AppendSwitchNative(switch_string, StringType());
}

void CommandLine::AppendSwitchPath(const std::string& switch_string,
    const FilePath& path)
{
    AppendSwitchNative(switch_string, path.value());
}

void CommandLine::AppendSwitchNative(const std::string& switch_string,
    const CommandLine::StringType& value)
{
#if defined(OS_WIN)
    const std::string switch_key = ToLowerASCII(switch_string);
    StringType combined_switch_string(ASCIIToUTF16(switch_key));
#elif defined(OS_POSIX)
    const std::string& switch_key = switch_string;
    StringType combined_switch_string(switch_key);
#endif
    size_t prefix_length = GetSwitchPrefixLength(combined_switch_string);
    auto insertion = switches_.insert(make_pair(switch_key.substr(prefix_length), value));
    if (!insertion.second)
        insertion.first->second = value;
    switches_by_stringpiece_[insertion.first->first] = &(insertion.first->second);
    // Preserve existing switch prefixes in |argv_|; only append one if necessary.
    if (prefix_length == 0)
        combined_switch_string = kSwitchPrefixes[0] + combined_switch_string;
    if (!value.empty())
        combined_switch_string += kSwitchValueSeparator + value;
    // Append the switch and update the switches/arguments divider |begin_args_|.
    argv_.insert(argv_.begin() + begin_args_++, combined_switch_string);
}

void CommandLine::AppendSwitchASCII(const std::string& switch_string,
    const std::string& value_string)
{
#if defined(OS_WIN)
    AppendSwitchNative(switch_string, ASCIIToUTF16(value_string));
#elif defined(OS_POSIX)
    AppendSwitchNative(switch_string, value_string);
#endif
}

void CommandLine::CopySwitchesFrom(const CommandLine& source,
    const char* const switches[],
    size_t count)
{
    for (size_t i = 0; i < count; ++i) {
        if (source.HasSwitch(switches[i]))
            AppendSwitchNative(switches[i], source.GetSwitchValueNative(switches[i]));
    }
}

CommandLine::StringVector CommandLine::GetArgs() const
{
    // Gather all arguments after the last switch (may include kSwitchTerminator).
    StringVector args(argv_.begin() + begin_args_, argv_.end());
    // Erase only the first kSwitchTerminator (maybe "--" is a legitimate page?)
    StringVector::iterator switch_terminator = std::find(args.begin(), args.end(), kSwitchTerminator);
    if (switch_terminator != args.end())
        args.erase(switch_terminator);
    return args;
}

void CommandLine::AppendArg(const std::string& value)
{
#if defined(OS_WIN)
    DCHECK(IsStringUTF8(value));
    AppendArgNative(UTF8ToWide(value));
#elif defined(OS_POSIX)
    AppendArgNative(value);
#endif
}

void CommandLine::AppendArgPath(const FilePath& path)
{
    AppendArgNative(path.value());
}

void CommandLine::AppendArgNative(const CommandLine::StringType& value)
{
    argv_.push_back(value);
}

void CommandLine::AppendArguments(const CommandLine& other,
    bool include_program)
{
    if (include_program)
        SetProgram(other.GetProgram());
    AppendSwitchesAndArguments(this, other.argv());
}

void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper)
{
    if (wrapper.empty())
        return;
    // The wrapper may have embedded arguments (like "gdb --args"). In this case,
    // we don't pretend to do anything fancy, we just split on spaces.
    StringVector wrapper_argv = SplitString(
        wrapper, FilePath::StringType(1, ' '), base::TRIM_WHITESPACE,
        base::SPLIT_WANT_ALL);
    // Prepend the wrapper and update the switches/arguments |begin_args_|.
    argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
    begin_args_ += wrapper_argv.size();
}

#if defined(OS_WIN)
void CommandLine::ParseFromString(const string16& command_line)
{
    string16 command_line_string;
    TrimWhitespace(command_line, TRIM_ALL, &command_line_string);
    if (command_line_string.empty())
        return;

    int num_args = 0;
    wchar_t** args = NULL;
    args = ::CommandLineToArgvW(command_line_string.c_str(), &num_args);

    DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
                           << UTF16ToUTF8(command_line);
    InitFromArgv(num_args, args);
    LocalFree(args);
}
#endif

CommandLine::StringType CommandLine::GetCommandLineStringInternal(
    bool quote_placeholders) const
{
    StringType string(argv_[0]);
#if defined(OS_WIN)
    string = QuoteForCommandLineToArgvW(string, quote_placeholders);
#endif
    StringType params(GetArgumentsStringInternal(quote_placeholders));
    if (!params.empty()) {
        string.append(StringType(FILE_PATH_LITERAL(" ")));
        string.append(params);
    }
    return string;
}

CommandLine::StringType CommandLine::GetArgumentsStringInternal(
    bool quote_placeholders) const
{
    StringType params;
    // Append switches and arguments.
    bool parse_switches = true;
    for (size_t i = 1; i < argv_.size(); ++i) {
        StringType arg = argv_[i];
        StringType switch_string;
        StringType switch_value;
        parse_switches &= arg != kSwitchTerminator;
        if (i > 1)
            params.append(StringType(FILE_PATH_LITERAL(" ")));
        if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
            params.append(switch_string);
            if (!switch_value.empty()) {
#if defined(OS_WIN)
                switch_value = QuoteForCommandLineToArgvW(switch_value, quote_placeholders);
#endif
                params.append(kSwitchValueSeparator + switch_value);
            }
        } else {
#if defined(OS_WIN)
            arg = QuoteForCommandLineToArgvW(arg, quote_placeholders);
#endif
            params.append(arg);
        }
    }
    return params;
}

void CommandLine::ResetStringPieces()
{
    switches_by_stringpiece_.clear();
    for (const auto& entry : switches_)
        switches_by_stringpiece_[entry.first] = &(entry.second);
}

} // namespace base
